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發表於 2015-1-4 23:37:52
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Imagine if you hold a wine glass in your hand and you gently give the edge of the bowl a flick with your nail, the resonance from the air in the bowl shimmers into the room, gently moving the air in all directions equally. That is how sound is created in nature and a loudspeaker is supposed to mimic nature.
Why is it then, that 99% of speakers throw the sound forward towards the listening position? That doesn’t seem quite right. The concentration of sound waves emitted by the speaker in one particular direction can and frequently does excite the room, distorting the sound causing all sorts of peaks and dips. Not good!
There is a school of thought that speakers should imitate the nature of natural sound propagation – sound created should propagate its energy equally in all directions. In doing so, the sound wave excites the room less, has a more natural decay, hence sounding tonally more natural to our ear. Duevel, a loudspeaker manufacturer from Germany, is one such advocate of the ‘Omni Directional Loudspeaker’ theory. We reviewed the entry model, The Planet, last year in MOD AudioVideo magazine. The execution of the Planet is limited by the need for simplicity in the construction to keep the cost down for an omni directional loudspeaker. There are better speakers from Duevel and today we introduce the Duevel Bella Luna Diamante, the second model from the flagship Sirius.
If we pit the Planet as the equivalent of say, a Mazda MX-5 Miata, the Bella Luna is a Porsche 911. Standing at one meter tall, the Bella Luna oozes class – it has the looks of a traditional loudspeaker – glossy wood veneer rather than the funky coloured laminate on the Planet. However, that’s where the traditional ends and the omni directional speaker kicks in – to achieve an omni directional dispersion – it makes use of lenses – or at least that’s what I will call them. Fabricated from layered ply, the lens forces the downward firing tweeter to disperse the sound energy in a 360 degrees radiation pattern – front, back, left and right. The only direction missing is towards the ceiling – for a good reason, every room’s ceiling is not of the same height and hence it will make the speaker sound markedly different. The tweeter is kinda big – 44mm equates to about 1.5-inch. A large tweeter like this one is capable of reaching low enough to the midrange region and it does – it crosses over to the bass drive unit at an incredibly low frequency of about 1 kHz! The 8-inch bass drive unit is mounted on the top of the cabinet and fires upwards into the lens, which then re-directs the sound energy to the four sides as well. As such, the sound propagation of the tweeter and bass driver is closely ‘coupled’ – the end result is an exceptional coherence in the sound of the two drivers – as if it is a single full range drive unit.
The cabinet is ported and it is located at the bottom of the enclosure – it vents downwards to the floor. The crossover of the Bella Luna is said to be very gentle and benign – suitable for low powered (tube?) amplifiers. At the back of the speaker where the speaker posts are, there is a switch to turn on and off the Phase Linear crossover. Possibly it is a Zobel network to even out the impedance of the crossover. Placement of this speaker is flexible – being omni directional, there is no need for any sort of toe-in, just avoid corners and allow a little space from the back and side walls will do. If you can afford the space, then pulling the speaker further out into the room will offer a more three dimensional presentation.
Sonically, the Bella Luna excels in the coherence of the tweeter and bass driver. The recreation of the soundstage between the two speakers is realistic and tonally mellow (but not rolled-off) and well fleshed-out. This loudspeaker will appeal to more experienced music lovers who find many ‘modern’ loudspeakers sound overly ‘impressive’. Impressive to listen to for a few minutes, but listening fatigue sets in soon after that! In contrast, the Bella Luna shows a restrain from doing just that. As such, you can sit back with a glass of scotch and enjoy a great musical performance. A good loudspeaker should recreate the performance to your music room as naturally as possible, with no emphasis or preference. The Bella Luna
Diamante with its omni directional technology does just that.
RCP S$16,000
2-way Omni directional loudspeaker
44mm tweeter with neodymium magnets
22cm woofer
Phase Linear crossover 6 ohms
Sensitivity 91 dB
Power handling: 150 watts rms
Frequency Response 40 – 23000 Hz
Duevel website: http://www.duevel.com/home/loudspeaker.shtml |
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發表於 2015-1-3 13:04:53
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